Where, in any municipality having 15,000 or fewer inhabitants and located in a county having more than 3,000,000 inhabitants, prior to the time this Act becomes effective, the corporate authorities of the municipality adopted an ordinance levying a tax for corporate purposes and filed a certified copy of that ordinance with the county clerk on or before June 1, 1989, that ordinance and any tax levied and extended pursuant thereto are declared to be legal and valid, notwithstanding that the ordinance was not adopted or filed with the county clerk within the time otherwise required by law.